/*
* Z80SIM - a Z80-CPU simulator
*
* Copyright (C) 1987-92 by Udo Munk
*
* This modul of the simulator contains a simple terminal I/O
* simulation as an example. It is released to the public domain
* and may be modified by user.
*
* History:
* 28-SEP-87 Development on TARGON/35 with AT&T Unix System V.3
* 11-JAN-89 Release 1.1
* 08-FEB-89 Release 1.2
* 13-MAR-89 Release 1.3
* 09-FEB-90 Release 1.4 Ported to TARGON/31 M10/30
* 20-DEC-90 Release 1.5 Ported to COHERENT 3.0
* 10-JUN-92 Release 1.6 long casting problem solved with COHERENT 3.2
* and some optimization
* 25-JUN-92 Release 1.7 comments in english
*/
/*
* Sample I/O-handler
*
* Port 0 input: reads the next byte from stdin
* Port 0 output: writes the byte to stdout
*
* All the other ports are connected to a I/O-trap handler,
* I/O to this ports stops the simulation with an I/O error.
*/
/*
* Forward declarations of the I/O functions
* for all port addresses.
*/
BYTE io_trap();
BYTE p000_in(), p000_out();
/*
* This two dimensional array contains function pointers
* for every I/O port (0 - 255), to do the needed I/O.
* The first entry is for input, the second for output.
*/
static BYTE (*port[256][2]) () = {
{ p000_in, p000_out } /* port 0 */
};
/*
* This function is to initiate the I/O devices.
* It will be called from the CPU simulation before
* any operation with the Z80 is possible.
*
* In this sample I/O simulation we initialize all
* unused port with an error trap handler, so that
* simulation stops at I/O on the unused ports.
*
* See the I/O simulation of CP/M for a more complex
* example.
*/
void init_io()
{
register int i;
for (i = 1; i <= 255; i++)
port[i][0] = port[i][1] = io_trap;
}
/*
* This function is to stop the I/O devices. It is
* called from the CPU simulation on exit.
*
* Here is just nothing to do, see the I/O simulation
* of CP/M for a more complex example.
*/
void exit_io()
{
}
/*
* This is the main handler for all IN op-codes,
* called by the simulator. It calls the input
* function for port adr.
*/
BYTE io_in(adr)
BYTE adr;
{
return((*port[adr][0]) ());
}
/*
* This is the main handler for all OUT op-codes,
* called by the simulator. It calls the output
* function for port adr.
*/
BYTE io_out(adr, data)
BYTE adr, data;
{
(*port[adr][1]) (data);
}
/*
* I/O trap funtion
* This function should be added into all unused
* entrys of the port array. It stops the emulation
* with an I/O error.
*/
static BYTE io_trap()
{
cpu_error = IOTRAP;
cpu_state = STOPPED;
return((BYTE) 0);
}
/*
* I/O function port 0 read:
* Read next byte from stdin.
*/
static BYTE p000_in()
{
return((BYTE) getchar());
}
/*
* I/O function port 0 write:
* Write byte to stdout and flush the output.
*/
static BYTE p000_out(data)
register BYTE data;
{
putchar((int) data);
fflush(stdout);
}
